1. Identification of chemical compounds responsible for
malodors in the animal by-products processing industry
Carlos D. Vaz 1,*, Rui M. Ramos1, Inês M. Valente1,2, Hugo M. Oliveira2, Margarida R. Maia2, Elisabete Matos3,
António J. M. Fonseca2, Ana R. J. B. Cabrita2 and José A. Rodrigues1
1 REQUIMTE/LAQV – Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Portugal
2 REQUIMTE/LAQV – Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal
3 Soja de Portugal, Ovar, Portugal
* duartevaz1994@hotmail.com
Abstract
• Nitrogen compounds
• Sulfur compounds
Protein
degradation
• Aldehydes
• Ketones
• Fatty acids
Fat degradation
Malodors
The gaseous emissions from animal by-products processing industries are an environmental concern mainly due to the
malodors that can be felt by the surrounding populations. They result from a variety of chemical compounds formed during
the chemical and microbiological decomposition of the residues. The control of these odors and of their release to the
environment is a priority for these industries, and the chemical characterization of the gaseous emissions is very important
to select the most adequate processes to control them.
In this work, a membrane-based sample preparation technique named gas-diffusion microextraction (GDME) was used to
develop a methodology for the extraction and identification of some chemical compounds dormed by lipid degradation
(aldehydes and ketones) from animal by-products samples and from samples collected during the processing of these
products. The identification of the extracted compounds was performed by HPLC-UV-MS/MS analysis.
GDME device
Upper piece
Membrane
Lower piece
g
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α+β g
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Acceptor solution
2,4-Dinitrophenylhydrazine
(DNPH) at 0.25%, m/v in
acetonitrile-H2O (1:1)
5 mL for liquid Samples
or
5 g for solid samples
15 min; 50 ºC
HPLC-DAD-MS/MS conditions
• Stationary phase: Gemini C18 (150 x 4.6 mm; 3 μm)
• Mobile phase: acetonitrile and acetate buffer 10 mmol/L
in gradient mode at 0.4 mL/min
• Volume of injection: 20 µL
• UV detection range: 200-600 nm
• MS detection: negative mode in range m/z 100-1000
Results
Figure 1: HPLC-DAD chromatogram (at 360 nm) of a sample extract. UV maximum wavelengths and MS fragments of the identified
compounds are listed in Table 1.
Compounds tR/min λ max (nm) MS MS2 fragments (intensity) MS3 fragments (intensity)
3-hydroxybutanone 12.08 362 267.07
176.99 (100), 178.96 (84), 151.93 (73), 151.01 (37), 181.93
(24), 120.00 (13), 146.99 (13), 153.04 (11) 164.96 (10),
122.05 (9)
146.93 (100), 145.95 (21), 122.06 (12)
Acetaldehyde 16.95 367 223.05
179.01 (100), 163.01 (91), 178.05 (70), 151.96 (53), 150.99
(52), 153.00 (29), 119.96 (28), 177.08 (21)
150.97 (100), 119.90 (18)
DNPH dimer 18.51 348 363.03 317.05 (100) 287.08 (100)
Acetone 20.47 368 237.06
207.08 (100), 150.91 (98), 178.97 (82), 119.86 (24), 152.00
(23), 174.07 (22), 191.10 (12)
178.11 (100), 164.04 (92), 177.16 (53),
132.01 (26)
Propanal 21.97 364 237.06
162.94 (100), 178.93 (57), 191.03 (26), 151.97 (26), 150.99
(26), 192.12 (25), 120.02 (20), 152.97 (18)
105.02 (100), 133.03 (13)
Butanone 26.07 368 251.08
221.08 (100), 179.05 (46), 151.94 (37), 150.92 (31), 190.99
(10)
152 (100), 178 (17), 192 (10), 205 (10)
iso-butanal 26.68 363 251.08
162.94 (100), 178.99 (39), 205.01 (32), 150.95 (19), 119.85
(18), 151.95 (14)
105.02 (100), 163.08 (15), 132.98 (15)
iso-pentanal 30.02 363 265.09
162.99 (100), 179.08 (35), 152.02 (26), 235.16 (17), 153.10
(17), 150.94 (15), 219.03 (15), 119.91 (12)
104.94 (100), 135.02 (10)
Table 1: List of compounds identified in the samples extracts.
Acknowledgements
This work was supported by the project PP-IJUP2014-SOJA DE PORTUGAL-03. RMR (SFRH/BD/88166/2012), HMO (SFRH/BPD/75065/2010) and MRM (SFRH/BPD/70176/2011) wish to acknowledge FCT for their PhD and post-doctoral grants. IMV
(SFRH/BPD/111181/2015) wishes to acknowledge FCT for her post-doctoral grant funded by the Portuguese Ministry of Education and Science and by the European Social Fund within the 2014-2020 Strategic Framework.
Poultry fat
By-product
meal
Condensate from
meat processing
Water from processing
fish by-products
Condensate from
processing fish by-products
3-hydroxybutanone + + + +
Acetaldehyde + + + + +
Acetone + + + + +
Propanal + + + + +
Butanone +
iso-butanal + + + +
iso-pentanal + + +
Table 2: Identification of aldehydes and ketones in animal by-products and in samples from their processing.
• Several volatile aldehydes and ketones related to fat degradation were identified in the studied
samples;
• Differences in the carbonyl compounds presence were observed between samples;
• Acetaldehyde, acetone and propanal were detected in all the analyzed samples;
• Butanone was only identified in a water sample from the processing of fish by-products.
Experimental procedure
Step 1: Extraction of the analytes Step 2: HPLC-DAD-MS/MS analysis
g g
g
g
RT: 8.00 - 35.00
8 10 12 14 16 18 20 22 24 26 28 30 32 34
Time (min)
0
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uAU
NL:
1.49E6
Channel A
UV
InesValente_F
CUP_Agua_C
ola_Peixe_201
50922
3-hydroxybutanone
Acetaldehyde
Acetone
Propanal
Butanone
DNPH
iso-butanal
DNPHdimer
Analysis of samples from the animal by-products processing industryIdentification of aldehydes and ketones by HPLC-DAD-MS/MS
Ongoing work:
• Identification of carbonyl compounds in more samples from the animal by-products processing
plant;
• Quantification of the identified compounds in the studied samples;
• Identification of other chemical compounds related to chemical and/or microbial degradation of
animal by-products and that are responsible for malodors.